The present invention relates to a phase difference control component that comprises a phase difference control layer capable of improving antireflection and viewing angle and that can keep the spacing between opposite substrates, etc. constant during assembly without recourse to any special means. The phase difference control component of the invention may be applied to various displays inclusive of liquid crystal displays and electro-luminescence displays.
Various types of displays are put to practical use, and, for the most part, are used in combination with retardation films for the purpose of improving antireflection and/or making viewing angles wide. For a typical retardation film, a retardation film (a negative C-plate) having its optical axis vertical to its substrate and negative double-refraction anisotropy and a retardation film (a positive A-plate) having its optical axis horizontal to its substrate and positive double-refraction anisotropy are used alone or in combination. For instance, see Patent Publication 1.
Currently available retardation films (herein referred to as phase difference control components) include a stretched polycarbonate or other film, and a triacetyl cellulose film on which a liquid crystal material having double-refraction anisotropy is coated. However, there are problems in connection with reflection of light at an adhesive layer used for laminating a retardation film onto a linear polarizing plate or laminating a multilayer structure onto a multilayer display. Moreover, the thickness of the phase difference control component itself is not that negligible. One possible approach to solving those problems involves lamination of a polymerizable polymer material onto one substrate that forms part of a display, thereby forming a phase difference control component. For instance, when substrates are combined together to set up a liquid crystal display, however, it is required to keep the spacing between the opposite substrate constant. For this reason, spacer particles such as silica particles are usually spotted over both substrates prior to lamination. For instance, see Patent Publication 2.
Patent Publication 1
JP(A)10-153802 (pp. 12-13, nd FIG. 54)
Patent Publication 2
JP(A)6-148654 (page 2)
However, one problem with the phase difference control component fabricarted using a polymerizable liquid crystal is that its rigidity is not necessarily satisfactory. Another problem is that when the phase difference control component is located on the inside of a substrate, spacer particles come into spot contact with the phase difference control layer. Accordingly, as pressure is applied on the phase difference control layer, it tends to suffer from deformation enough large to permit spacer particles to engage therein. Thus, even when spacer particles having a constant particle diameter are used, it is often likely that the spacing between both substrates deviates from the diameter of the spacer particles; for instance, that spacing at the center of a display tends to become narrower than a given value.